XBee
From bildr
XBee is a wireless serial port replacement module. XBee modules are available in the following frequenties: 2.4 GHz, 900 MHz and 868 MHz. The GHz 2.4 modules can also be used in a mesh networking configuration in which the modules can sample data or drive a pin on the module.
Version 1 vs Version 2
(Please update)
Version 2 xbee is not an upgrade from version 1, and it does not mean that version 1 is out dated or going to stop being produced. Version 1/2 are different protocols and each has its own strengths and weaknesses.
Version 2 is great for mesh networks, where there is one parent, and many children sending data to that parent, but where the parent is not often sending data to the children.
Version 1 is much simpler and is great for one-to-one, two-way communication, essentially acting as a wired serial connection between 2 devices.
Reference
This page is an Article on bildr. Articles are pages that define or explain a concept, method, or generic item.